US3412492A - Steam iron - Google Patents

Description

Nov. 26, 1968 J. MCCORMACK 3,412,492

STEAM IRON Filed Aug. 10, 1967 2 Sheets-Sheet 1 INVENTOR LEONARD J. McCORMACK F/G. 5

BY W ATTORNEYS Nov. 26, 1968 1.. J. MCCORMACK STEAM IRON 2 Sheets-Sheet 2 Filed Aug. 10, 1967 United States Patent 3,412,492 STEAM IRON Leonard J. McCormack, Winchester, Va., assignor to Reimers Electra Steam, Inc., Clearbrook, Va., a corporation of New York Filed Aug. 10, 1967, Ser. No. 659,738 9 Claims. (CI. 3877) ABSTRACT OF THE DISCLOSURE An improved steam iron of the type which utilizes an external steam supply and comprises an upper or superheating section and a lower section or sole plate. A heating element is positioned between the upper section and the sole plate. Relatively small steam channels are located in the superheating section in close proximity to, and generally following the shape of, the heating element. A thermostat is located such that it senses temperature changes occurring both in the vicinity of the superheating channels and in the sole plate.

This invention relates to improvements in steam irons, and more particularly to electric irons of the type which utilize an external steam supply.

Hand irons which use steam from an external source of supply are widely used commercially for pressing or steaming various types of fabrics. When using such irons, care must be taken that the steam is so-called dry steam and free of condensed moisture. In most steam irons, the steam enters from an inlet and then goes to a series of ducts or chambers to be superheated before passing through apertures in the base of the sole plate where it contacts the material being pressed or steamed.

The superheating is necessary to remove condensed moisture which, if allowed to pass through the apertures, might stain or spot certain fabrics. In the superheating portion or section of the iron the steam is subjected to additional heat generally provided by an electrical heating element. The heating element is usually located in the upper or superheating portion of the iron so as to be relatively close to the steam passages and is often above the steam passages. Because of this, such irons suffer from the disadvantage of uneven heating of the sole plate and considerable heat is wasted in heating a large nonutilized mass in the upper portion of the iron. With such constructions the sole plate is heated by the steam passing therethrough before being ejected and, secondarily, by convention or conduction from the heated upper portion of the iron.

The prior art steam irons which contain an electric heating element also montain a thermostatic switch to control the temperature of the iron. The thermostat is connected in series with the heating element and controls the heating element responsive to temperature changes in the proximity of the thermostat. If, as in most steam irons, the thermostat is located close to the steam passages in the upper or superheating section of the iron, but at a distance from the sole plate, proper control of the sole plate temperature is difficult if not impossible. Conversely, if the thermostat is located in the sole plate section the superheating section of the iron may undergo wide variations in temperature without adequate compensation thereby permitting some of the steam to condense.

It is extremely important, particularly when working with synthetic fabrics, to have constant temperature control in order to prevent damage to the fabrics. Generally, lower temperatures must be used when pressing synthetic fabrics than are necessary for fabrics made of natural fibrous materials. When pressing synthetic materials with a conventional steam iron one must use a temperature setting sufiiciently low that the material will not be scorched. Yet, when this is done the temperature may be too low to properly superheat the steam, some of which may condense and cause water spotting of the fabric. It would be extremely desirable to use a steam iron which is constructed in such a way that the superheating section of the iron will be sufliciently hot to dry the steam while at the same time the sole plate will be at a proper temperature for contacting synthetic, as well as natural, materials.

Another important, but related, consideration in steam irons of the type described is that of heat transfer. Most of the steam irons currently in use possess relatively large steam channels in the superheating section of the iron. The large volume of steam passing through these channels requires considerable heat energy for superheating which, even then, may not be enough to completely prevent condensation. Additionally, when the iron is first turned on, the condensation remaining in the channels from the previous use must be either ejected or vaporized before the iron may again be used without water spotting. Several methods such as inclusion of metal wool to provide a greater heat transfer area have been suggested for improving the efliciency of prior art devices in order to obviate these shortcomings but these methods, however, also sutfer serious drawbacks. The location of the steam channels in relation to the heating element has not been taken into consideration heretofore even though such a relationship is important.

Accordingly, it is a primary object of this invention to provide a steam iron which is free of the aforementioned and other such disadvantages associated with steam irons of the prior art. Further, an important object of this invention is to provide a steam iron of the type utilizing an external source of steam and an internal heating element which efliciently transfers heat without external piping connections such as are necessary with prior art devices and which cause large radiation losses.

An additional object of this invention is to provide a steam iron suitable for pressing synthetic fabrics without causing any damage thereto while simultaneously drying steam passing therethrough to prevent water spotting.

Consistent with the preferred embodiment of this invention, the steam iron provided hereby includes an upper or superheating section and a lower or sole plate section with a heating element positioned therebetween and in direct conductive contact with both sections. Relatively small steam channels or ducts are located in the superheating section in close proximity to, and generally following the shape of, the heating element. Further, a thermostat is located such that it senses temperature changes occurring both in the vicinity of the superheating duct and in the sole plate whereby proper control of the temperature in both critical areas is possible and such thermostatic control is resiliently pressed into contact with a well provided thereto to insure good heat transfer and temperature control.

In one embodiment of this invention a steam iron is provided *which is suitable for steaming various fabrics, including synthetics, without coming into physical contact therewith yet which embodies the heat transfer and control principles herein described. Such a steam iron has variously been termed a steam gun and the terminology steam iron used throughout this specification and in the appended claims is intended to be generic to a device of this type as well as to any device which may be used in the garment or furniture industry or other such industry to supply dry steam to fabrics.

This invention will be better understood, and objects other than those set forth above will become apparent when consideration is given to the following detailed description. Such description refers to the annexed drawings presenting preferred and illustrative embodiments of the invention. In the drawings:

FIGURE 1 is a side elevational view of one embodiment of a steam iron according to this invention with the rear cover plate being broken away and hidden parts being shown in dotted lines for illustrative clarity;

FIGURE 2 is a horizontal cross-sectional view taken on line 22 of FIGURE 1 with the heating element being shown in phantom;

FIGURE 3 is a rear elevational view of the steam iron of FIGURE -1 showing the relative linear relationship between the heating element and the various steam channels;

FIGURE 4 is a diagrammatic transverse cross-sectional view showing the active heat zone of a steam iron according to this invention;

FIGURE 5 is a bottom plan view, to a reduced scale, of the steam iron of FIGURE 1;

FIGURE 6 is a side elevational view of a steam gun or modified steam iron according to this invention with the cover plate broken away;

FIGURE 7 is a top plan view of the steam iron of FIGURE 6, the cover plate being removed to show the relative placement of the electrical contacts; and

FIGURE 8 is a bottom plan view of the steam iron of FIGURE 6.

Like reference characters refer to like parts throughout the several views of the drawings.

Referring now to the drawings and more particularly to FIGURES l-S, a steam iron according to a preferred embodiment of this invention is generally designated at 2. The steam iron 2 comprises an upper or superheating section 10 and a lower or sole plate section 12. These may be cast as a single piece although, in the preferred embodiment, they are show-n as two separate elements secured together by bolts 47 and nuts 48. The lower face of the superheating section 10 and the upper face of the sole plate section 12 are recessed to provide a channel for a heating element to be seated therein in intimate contact with the walls of both the superheating section 10 and the sole plate section 12. The heating element 20 may be a conventional electrical heating element and is preferably essentially U- or horseshoe-shaped as can be seen in FIGURE 2 with the legs thereof lying generally longitudinally in the iron on either side of the longitudinal central axis, although, as will be recognized, other configurations can be used without departing from the instant inventive concepts.

A steam inlet 34 is provided at the rear of superheating section 10 and communicates by way of a bored passage 33 with a continuous superheating duct 22. Superheating duct 22 is also approximately horseshoe-shaped following a path which is generally juxtaposed with heating element 20. The placement of superheating duct 22 in close proximity with heating element 20 and generally juxtaposed thereto assists in the efficient heat transfer which is obtained with the steam iron of this invention.

The superheating duct 22 is preferably formed of communicating bores 22a, 22b and 220. The points of communication of the bores with the exterior of the iron are plugged either with a non-removable plug such as shown illustratively at or preferably with a removaible plug such as shown illustratively at 36 which is threadably engaged therein. The plugs 26 may be re moved for cleaning or draining the superheating duct 22. The superheating duct 22 could include other channels than those shown in the drawings, the basic concepts hereof requiring however that at least the major portion of the superheating duct generally follow at least the major portion of the heating element.

The sole plate section 12 contains a continuous sole plate duct 24 which communicates at the forward end portion of the sole plate section 12 with a plurality of steam exit passages or apertures 26 which project the steam generally downwardly onto the material being treated. Sole plate duct 24 is preferably bored along the longitudinal axis of the sole plate and the bore hole is also closed as with a plug 36.

The steam leaving superheating duct 22 from one of the horseshoe legs thereof passes through a conduit 44 and connecting tube 40 into sole plate duct 24. Once again, the sole plate duct 24 could take any desired configuration depending on the desired configuration of steam exit apertures 26 which may be varied depending on the particular application of the steam iron. In the preferred embodiment shown in the drawings at least the major portion of the sole plate duct is generally midway positioned between the leg portions of the horseshoeshaped heating element.

A thermostatic control 28 is mounted in a recess or well 38 provided for that purpose so that it is centered between the leg portions of the horseshoe-shaped superheating duct 22 and extends below the level thereof but above the level of the heating element 20. A spring 30 is fitted over control shaft 31 so that when cover plate 42 is in place the thermostat 28 will be securely seated in the recess 38 and in constant contact with the portions defining the bottom of the recess 38 for optimum heat transfer and temperature control. Graduations can be applied to cover plate 42 to enable the user to select the desired heat range.

The electrical circuit connecting the heating element 20, the thermostatic control 28, and the micro-switch '18 is conventional and is not shown in the drawings except to indicate the various wires generally designated 52. The micro-switch 18 serves no function within the iron but rather is connected to a solenoid valve (not shown) which allows steam from the supply to enter the hose atttached to the iron. An internal conduit shown in FIGURE 3 at 64 is provided for the wires 52 which connect to the thermostatic control 28 and the micro-switch 18. A wire 54 from the power source enters the steam iron through a suitable mounting clamp 5-8 and insulating block 16. It is apparent that conventional disconnect-able electrical lead-in means may be used. The connections of wires 52 to the heating element 20 are protected by a rear cover plate 50.

It will be noted from FIGURE 3 that in this preferred embodiment, the distance S from the heating element 20 to juxtaposed portions of the superheating duct 22 is approximately equal to the distance E from the heating element 20 to juxtaposed portions of the sole plate duct 24. This provides optimum heat transfer and control.

It can be appreciated from FIGURE 4 that the heat sensing and control area 56 is so located that it will sense temperature changes in the active heat zone 60 generally surrounding the heating element 20 and the ducts 22 and 24. The thermostat 28 can, therefore, control heating element 20 responsive to the heat requirements in the superheating section 10, or in the sole plate section 12 thereby providing more uniform heat throughout the iron and more efficient heat exchange between the heating element 20 and the steam flowing through the superheating duct 22 as well as between the heating element 20 and the sole plate section 12. It is also apparent that the steam channels are relatively small in cross-sectional area, and therefore in total volume, in comparison with the total mass of the iron and with the heating capacity of the heating element. This increases the heat transfer efiiciency and reduces the amount of condensed steam which must be vaporized on initial start-up, thereby reducing start-up time.

In the steam iron 2 of this preferred embodiment, steam enters through inlet 34 and travels through channel 33 to channel 22b of superheating duct 22, thence to channels 220 and 22a before passing through channel 44 and duct 40 to sole plate duct 24 which directs the steam to the exit aperatures 26. The setting of the thermostatic control 28 is changed by turning knob 32 according to the type of material being ironed. The heating element 20, through the efficient heat exchange provided by this invention, superheats the steam in duct 22 and simultaneously heats sole plate 12 to the required temperature. The micro-switch 18 is mounted on bracket -17 so that it is convenient to the user when he grips handle 14.

Turing now to another embodiment of this invention, reference is made particularly to FIGURES 68 wherein a steam iron in the form of a steam gun which is suitable for steaming a fabric without necessarily contacting the same with the sole plate is shown generally at 102. The heating element 120 thereof is located in a recess in the lower face of the superheating section cooperating with an opposed recess in the upper face of the sole plate section 112. The electrical contacts for the heating element are provided above the superheating section 110 and a bored passage located at the rear of superheating section 110 communicates with the heating element recessed for this purpose.

The heating element 120 of this embodiment is essentially horseshoe-shaped with the legs of the horseshoe converging toward the rear of the steam iron since such a configuration is convenient for devices of this type. The superheating duct 122 comprises three communicating bores 122a, 12212, and 1226 provided with plugs at the bore holes thereof. Once again, superheating duct 122 approximates the shape of heating element 120 and is generally juxtaposed therewith and in close proximity thereto.

Steam inlet 134 communicates with steam channel 122a, and bore 144 connects steam channel 12211 with duct which in turn carries the dried steam downwardly to sole plate duct 124. As in the previous embodiment, the superheating duct 122 could take other configurations without departing from the instant inventive concepts. In this steam gun, the sole plate duct 124 comprises T-shaped bores 124a and 124b with steam outlet aperatures 126 being spaced along transverse bore 124b. This, thus, illustrates another configuration for the distribution of steam to the material being treated.

Superheating section 110 and sole plate section 112 are securely joined by any suitable means such as screws which project through mounting holes 148 as shown in FIGURE 7 that have been omitted from FIGURE 6. Similarly, cover is secured in place by screws which engage mounting holes 149.

Thermostatic control 128 is inserted in a recess 138 and is secured in place by leaf spring 130. The thermostatic control 128 is approximately centered between the legs of the superheating duct 122 extending below the level thereof but above the level of heating element 120. Knob 132 mounted on shaft 131 is located for easy adjustment of the thermostatic control 128.

The electrical circuit and connections are conventional, with the wires being generally designated 152. The leadin wire 154 is protected by a conventional mounting clamp 158. The handle 114 is mounted by means of brackets 117 above the insulated steam inlet pipe 134 for ease of handling. The lead-in wire 154 extends through the center of the handle 114.

In use the steam gun version of the steam iron of this invention, the heating element is adjusted for the proper tempearture range by turning knob 132 which controls the thermostat 128. Steam from an external source enters the superheating section 110 through inlet 134, travels through the superheating duct 122 to be dried out before proceeding through bore 144 and duct 140- to sole plate duct 124 to exit therefrom through steam outlet apertures 126.

The efiicient heat transfer and the portability of this steam gun enable the user to direct steam toward a material, which may he a synthetic material, in order to remove wrinkles therefrom and rejuvenate the same. In this manner such articles as draperies may have wrinkles removed therefrom without removing them from their permanent location.

Thus, it is apparent that the foregoing objects of this invention have been satisfied by reference to the preferred embodiments thereof which are merely illustrative and not to be considered limiting.

What is claimed is:

1. A steam iron comprising a superheating section having a lower face and a sole plate section having an upper face juxtaposed to said lower face of said superheating section, said sections each having a front end and a rear end and together form a common longitudinal central axis, said superheating section including portions defining a continuous superheating duct having an inlet end and an outlet end, a steam inlet port connected to said inlet end of said superheating duct, said superheating duct including, between said inlet and outlet ends of the same, at least one leg portion extending generally longitudinally of said superheating section on each side of said central axis, portions of said superheating section and portions of said sole plate section together defining channel means between said lower face of said superheating section and said upper face of said sole plate section, respectively, a heating means seated in said channel means and in direct contact with said portions of said superheating section and said portions of said sole plate section defining said channel means, said heating means including at least one leg portion extending generally longitudinally of said iron on each side of said central axis, said sole plate section including portions defining a continuous sole plate duct having an inlet end, passageway means connecting said outlet end of said superheating duct with said inlet end of said sole plate duct, and a plurality of steam outlet apertures defined in said sole plate section in communication with said sole plate duct, the shape of at least the major portion of said superheating duct generally corresponding to the shape of at least the major portion of said heating means.

2. A steam iron as defined in claim 1, wherein both said superheating duct and said heating means are approximately horseshoe-shaped.

3. A steam iron as defined in claim 2 wherein said leg portions of said superheating duct are substantially parallel.

4. A steam iron as defined in claim 3 wherein said major portion of said superheating duct is spaced from juxtaposed portions of said heating means a distance approximately equal to the spacing of at least a major portion of said sole plate duct from juxtaposed portions of said heating means.

5. A steam iron as defined in claim 4, wherein at least the major portion of said sole plate duct is a straight passageway positioned along said central axis approximately midway between said leg portions of said heating means.

6. A steam iron as defined in claim 1 wherein said leg portions of said superheating duct and said heating means are tapered inwardly toward the rear end of said superheating section.

7. A steam iron as defined in claim 1, wherein at least the major portion of said sole plate duct is a straight passageway positioned along said central axis approximately midway between said leg portions of said heating means, further including a transversely disposed straight passage way communicating with the forward end of said major portion of said sole plate duct, said plurality of apertures communicating with spaced portions of said transversely disposed straight passageway.

8. A steam iron as defined in claim 1, wherein said superheating and sole plate ducts comprise relatively narrow bores containing removable plugs at the points where said bores communicate with the exterior surfaces of said superheating and sole plate sections respectively.

9. A steam iron as defined in claim 1 wherein said super-heating section further contains a thermostatic heat control recessed therein approximately centered between said leg portions of said superheating duct to a depth below the level of said superheating duct and above said lower face of said superheating section, said heating means and said thermostatic heat control being electrically operable and being conductively connected to an external source of electricity.

8 References Cited UNITED STATES PATENTS 2,078,061 4/1937 Cooper 38-77 2,353,604 7/ 1944- Waring et a1 3877 2,533,995 12/ 1950 Chapin 38--77 2,664,654- 1/1954 Dickman 38-77 PATRICK D. LAWSON, Primary Examiner.

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